Products in liquid form have for many years been packaged in a variety of containers suitable for shipping, displaying. handling and eventual sale. These containers have been made in a great variety of shapes and sizes with different types of closures. They include glass containers, and containers of synthetic materials which have been moulded, blow-moulded and generally formed into shape. Also, because of the nature of these plastics materials, the closures can be of many various types including screw caps, flip tops, and simple bonded seals. In general, containers of these types have been made to enhance the appearance and visual affect of the product.
Some liquids packaged in such containers are used in small quantities and is convenient to dispense such liquids in the form of a foam provided of course that the liquid is suitably formulated.
The limitations to dispensing foam are found in the complex structures previously used to create foam. These structures are desirable in order to minimize the use of aerosol containers designed to create foam but the cost of the structures and the difficulties of recycling structures having many different materials have severely limited the use of dispensing structures for foam.
Some very simple dispensers are taught by the present applicant in U.S. Pat. Nos. 4,324,349; 4,635,828; 4,645,097 and 5,033,653. Such dispensers have become known as Kaufman dispensers (after the inventor). The dispensers have no moving parts and yet satisfy the requirements of clean dispensing with temperature compensation to permit the dispenser to be subjected to a designed range of temperature fluctuation without inadvertent dripping or dispensing.
The structures shown in the applicant's earlier patents have a self-contained reservoir containing some of the liquid to be dispensed and in communication with the main part of the dispenser which is in the form of a container where the major volume of the liquid is stored. Air is trapped above the liquid in the container under a negative pressure to establish equilibrium and thereby prevent liquid flowing through the reservoir and out through a discharge passageway. When the negative pressure is disturbed, liquid will tend to flow out of the container and into the reservoir, then out via the passageway. As soon as the negative pressure is restored by sucking air back through the passageway, a condition of equilibrium is again achieved. As the air is sucked back, liquid is cleaned out from the passageway and some of the air finds its way through the liquid to finish above the liquid in the container while some remains in the reservoir.
The embodiments of the present invention include dispensers based on the Kaufman technology as well as others which use simple squeeze-bottles as a basis.